CERTAIN DISTINCT ADVANCES IN THE ANALYTICAL CHEMISTRY OF RECENT YEARS.’ I- AI.Ill.:KT TI.
I’KESCIITT.
0
F the important gaitis made 1)y the present generation of
chemists let us acknowledge i I ) the resolute attempt to find out the coinposition of niattcr ;is a whole i n any and all of its mixtures of whatever source. rlnalytical workers have undertaken to resolve the coniplex iiiass and account for all its contents. It has been their aiiibition to identify mid determine existing molecules of every sort withiii a given mixture, while sl-nthetical workers have sought to reach the constitution of the molecules themselves. T h e task of coiiiplete analysis has been entered upon, that called “prosiniate ” as well as that called “ultiinate.” There have been good investigations that have taken extractive matter ” ant1 I ’ empyreumatic matter” and “ bituminous matter ” arid other undetermined residues as subjects for tlie beginning of cheniical work rather than the eiicl of it. T h e task of tlie COIIIplete aiialys’is of matter in its ever)- possible portion is a task that has been recognized arid entered upon as ;i necessity of chemical advaricemeiit. I do not ~ J J -any riieans infer that the determination of distinct cornpouiitis is tlie 1-esult of analytical chemistry alone, as but oiie of the divisions of the science. On the contrary I would emphasize the dependence of the analyst upon the entire body of c1iemic:il learniiig. He is liniited by this dependence even for the identification aiid estimation of distinct bodies without going into the make-up of iiiolecules. Analysis is or ought to be a certain function of the whole body of chemistry, not a part of the body ivliicli could live if separated. A n arialyst can not well he less than a whole chemist, arid though his ends be jingle iii direction, they are not indifferent to the powers coniin011to all chemical insight. T h e analj-tic method began to yield large returns in the last century. When Black made more exact qualitative exarninatioii of fixed air he began to uncover that chain of underlying truth laid hold of by Priestley and fairly dislodged by Lavoisier and other contemporaries. 111the first half of this century t h e I ‘
1
Read before t h t World’s Cotigress of
Cheinists,
August
22,
189;.
ADVANCES I N ANALYTICAL CHEMISTRY.
377
enormous analytical detail instituted by Berzelius extended the very foundations of physical science. And in the present generation the analyses of biological chemists and industrial chemists of many and various purposes have been very influential factors in the support of great principles of chemical truth. Again, the courage of analytical effort in recent years has been seen especially ( 2 ) I n the elaboration of methods for the isolation of carbon compounds, both natural and artificial. “ Proximate organic analysis” is not so greatly at a discount as it was twenty years ago. Research has been devoted to the estimation of organic compounds, unbroken and unaltered. It has been a common necessity to effect determinations truly proximate,” in the definition of this inadequate word. There have been pointed inquiries from the biologist often, from the metallurgist at times, from the theoretical chemist not seldom, what is the chemical character of this body as its exists just before its analysis? Since Dragendorff devised ways of plant analysis, and HoppeSeyler collected methods of physiological analysis, thousands of contributions have enriched the resources of the organic analyst and thousands of workers are now in like endeavor. Chemical literature is thickly strewn with directions for analysis to the end of the identification of the integral molecule, representing matter in its living state, if such a figure of speech may be used. This is indeed the special task of analytical research, although the terms of analysis are also given to operations that accompany synthetic work, to wit : (3) I n studies of the molecular structure of bodies produced by nature, bodies mineral, vegetable, and animal, as well a s those of artificial production. To classify analytical work strictly by definition, which, however, I have no desire to do, all the studies of molecular constitution come within the range of analytical inquiry. But even under customary classification of chemical labor, it will be observed that certain instruments of observation early used by analytical chemists have since been found most effective in studies of molecular structure even for what is termed the configuration of the molecule. Especially, therefore,
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DV.\ N C E S IX -IS.\T.YTIC.1 I. C H 1: AI I ST I:Y .
( 4 ) In the employnient oi pli!.s;ical methods of iuspection, whereby molecular c l ~ a n g eis a\.oic!etl, iiiiportaiit arl~.ailceshat-c been iiiade iii the ~ i i a l y s eof~recciit \.ears. First of all through the ,se\.eral rcspiises of tlic molecule to light, uiider more cs'ict ulxervation. thc: clearest 01 ideiitificatioiis liave been obtaiiietl. Optical methods 1iaI.e iiiultiplied aii(1 become more exact. 11-c a r c . lio\ve\.rr, oiil!. in the lxgiiiiiiiig of their adaptation to analysis. Stuc1it:s of xeoiiietric isoiiierisiii have shon-11 tlic analyst lion. rich i i i results tlie polariiiieter iii:i! beconic. S e s t to this, pro1)al)ly. htaii(13 the rciractoiiieter ill its value a s a i i i e a ~ i sof recognition i n :iii:il! sis. 'I'licii tlie u s e of the spectroscope for stiidies of absorptioii 1., ti-niisI);irtmt Iiodies has :dread)- done acliiiirable service to analysis, lwth orgaiiic and inorganic. S e n . rc:spoiises of iiiatter to lirat lia\-c- heeii hrought uiider observatioii. In clunlitntive t1eteriiiiii:itioii. as i n tlie finding of the iiiolecular 111 tlic. freezing poiiit aiitl the effect on solidifying points of solveiits arc i i i questioii as well as tlie iiieltiiig points and Iioiliiig points. T h e clieiiiicnl Tvorltl is alive with interest i i i the admiices of the i i e ~ vph!.sical cliemistr!.. T o these atlvaiices no one is a n d is to i x iiiQre iiitlehtecl than tlie analyst. Solu1)iIity itself. the great coiiiiiioii factor of analytical operation. is uiitler iii\-estigatioiis in \vliicli tlie alialyst has tile keenest interest. l'lic ieeliler iiiflueiicvs of :idliesion, too often o\-erlookecl, causiiig ivaste i i i cltiniititntil-c. scl)arations and putting limits upoii tlic best of OIIT results !or aiial!.tical recovery, these, \\.it11 the plieiioiiieiin (,I capillnrit!., oi coiitrol are well riiitler iiir,estigation. '1'11~. i . e l - ~chccks analyses s e n e as data for studies iii iiioiecular physics. It is riot possible for i i ~ eto group togctiier in i*la~ses near all the ways of advance in recent alidytical clienii?try, aiid I will but specif). once more Iiow this adsaiice appears (j) In tlie reciprocal lxiiefits O i sciciitific research arid of technical skill. 1 l T e see this i i i tlie ivork oi experts, those iii biological and pathological niialysis, sanitary :ind forensic analysis, industrial and coniiiiercial analysis, agricultural and metallurgical analysis. Chemical literature during the last teii \-ears s1ion.s how promptly discoveries like those of Eiiiil Fisclier i l l the sugar group, or those of Ladeiiburji u l m i hydrolysis of
ARTIFICIAL PRODUCTION O F PETROLEUM.
379
alkaloids, those of Gladstone on refraction equivalents, or those of Baeyer upon the phthaleins, become well reduced to practice in the operations of analytical work. T h e simple volumetric estimations of acid and alkali are expanded in ten-fold application in thousands of analytical laboratories by means of varied indicators from the color discoveries of coal tar chemists such as Otto Witt. Analysis bows its acknowledgment of indebtedness to synthetic research. T h e interests of the section of analytical chemistry are all interwoven with the interests of all the sections of this congress. T h e analytical chemist will be a good listener to all the papers in the rich and varied repertory of the week before us.
ON THE ARTIFICIAL PRODUCTION OF PETROLEUM. BY DR.C. ENGLER.
S
CIENTISTS have discussed very often in the last few years
the question in which way petroleum, this source of wealth, with its special scientific interest for this country, was formed by nature. According to one theory it is generated from inorganic materials. Sokoloff thinks, that petroleum was produced during the period of the formation of our planet out of cosmical hydrocarbons, which in the beginning dissolved in the soft mass, separated from it later on. Mendelejeff assumes that water entering by fissures and chasms the interior of the earth came in contact with melting carbide of iron and produced so in a simple manner oxide of iron and the hydrocarbons of petroleum. Strong objection cannot be made to these two theories from the chemical standpoint; but the composition of the different kinds of petroleum is against them, and geology considers them not free from objections. For a series of years the idea that petroleum was produced from the remains of plants by a kind of a distillation process, was most generally adopted, especially by chemists. Chemical and geological reasons are against this theory. From the chemical standpoint it seems quite impossible that the substance of the plants could be split up by distillation into petroleum without 1Read before the World's Congress of Chemists, August 23, 1893.
